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📆 Date & Age Workspace
Three date modes for ages, signed differences, and adding or subtracting calendar days.
Results update as you type. Use Reset current mode to restore the example. Copy mode link shares the selected formula, not your entered values. Display precision changes presentation only.
Available calculations
Formula, standards and limitations
Age is expressed in completed years as of the reference date. People born on February 29 have different legal birthday conventions in non-leap years; this tool uses the actual month/day anniversary and therefore counts March 1. Date difference is signed: end minus start.
How to use this tool
Choose a calculation mode, enter valid inputs, and read the result. Each mode is linked from the directory. Calculations happen on your device, with no required account or paid API. Verify consequential financial or technical decisions independently.
Explore the full converter and calculator directory or all OpenToolKit tools.
Additional calculation notes
Adding days uses calendar dates in UTC and does not account for business days, holidays or local cut-off times.